According to reports over at Aint It Cool - Here – the new Avengers movie is not only “how and why” that brings together Cap, Tony start, Hulk, Thor and assorted other characters but also introduces the mainstream audience to the cosmic aliens of the Marvel Universe.

“‘The Avengers” script will blend ‘Iron Man’, ‘Thor’, and ‘Captain America: The First Avenger’ story lines as the Avengers battle with two alien races, the Skrulls and the Kree.”